Distal protection device and method

ABSTRACT

An emboli capturing system captures emboli in a body lumen. A first elongate member has a proximal end and a distal end. An expandable emboli capturing device is mounted proximate the distal end of the first elongate member, and is movable between a radially expanded position and a radially contracted position. When in the expanded position, the emboli capturing device forms a basket with a proximally opening mouth. A second elongate member has a proximal and a distal end with a lumen extending therebetween. The lumen is sized to slidably receive a portion of the first elongate member. An expandable delivery device is mounted to the distal end of the second elongate member and is movable from a radially retracted position to a radially expanded position. The delivery device has a receiving end configured to receive the emboli capturing device, and retains at least the mouth of the emboli capturing device in a radially retracted position.

[0001] This application is a continuation-in-part of co-pendingapplication Ser. No. 08/810,825 filed Mar. 6, 1997 entitled DISTALPROTECTION DEVICE, and assigned to the same assignee as the presentinvention.

[0002] The following co-pending patent application is herebyincorporated by reference U.S. patent application Ser. No. 08/813,794,entitled DISTAL PROTECTION DEVICE which was filed on Mar. 6, 1997, andassigned to the same assignee as the present application.

BACKGROUND OF THE INVENTION

[0003] The present invention deals with an emboli capturing system. Morespecifically, the present invention deals with an emboli capturingsystem and method for capturing embolic material in a blood vesselduring an atherectomy or thrombectomy procedure.

[0004] Blood vessels can become occluded (blocked) or stenotic(narrowed) in one of a number of ways. For instance, a stenosis may beformed by an atheroma which is typically a harder, calcified substancewhich forms on the lumen walls of the blood vessel. Also, the stenosiscan be formed of a thrombus material which is typically much softer thanan atheroma, but can nonetheless cause restricted blood flow in thelumen of the blood vessel. Thrombus formation can be particularlyproblematic in a saphenous vein graft (SVG).

[0005] Two different procedures have developed to treat a stenoticlesion (stenosis) in vasculature. The first is to deform the stenosis toreduce the restriction within the lumen of the blood vessel. This typeof deformation (or dilatation) is typically performed using balloonangioplasty.

[0006] Another method of treating stenotic vasculature is to attempt tocompletely remove either the entire stenosis, or enough of the stenosisto relieve the restriction in the blood vessel. Removal of the stenoticlesion has been done through the use of radio frequency (RF) signalstransmitted via conductors, and through the use of lasers, both of whichtreatments are meant to ablate (i.e., super heat and vaporize) thestenosis. Removal of the stenosis has also been accomplished usingthrombectomy or atherectomy. During thrombectomy and atherectomy, thestenosis is mechanically cut or abraded away from the vessel.

[0007] Certain problems are encountered during thrombectomy andatherectomy. The stenotic debris which is separated from the stenosis isfree to flow within the lumen of the vessel. If the debris flowsdistally, it can occlude distal vasculature and cause significantproblems. If it flows proximally, it can enter the circulatory systemand form a clot in the neural vasculature, or in the lungs, both ofwhich are highly undesirable.

[0008] Prior attempts to deal with the debris or fragments have includedcutting the debris into such small pieces (having a size on the order ofa blood cell) that they will not occlude vessels within the vasculature.However, this technique has certain problems. For instance, it isdifficult to control the size of the fragments of the stenotic lesionwhich are severed. Therefore, larger fragments can be severedaccidentally. Also, since thrombus is much softer than an atheroma, it,tends to break up easier when mechanically engaged by a cuttinginstrument. Therefore, at the moment that the thrombus is mechanicallyengaged, there is a danger that it can be dislodged in large fragmentswhich would occlude the vasculature.

[0009] Another attempt to deal with debris severed from a stenosis is toremove the debris, as it is severed, using suction. However, it may benecessary to pull quite a high vacuum in order to remove all of thepieces severed from the stenosis. If a high enough vacuum is not used,all of the severed pieces will not be removed. Further, when a highvacuum is used, this can tend to cause the vasculature to collapse.

[0010] A final technique for dealing with the fragments of the stenosiswhich are severed during atherectomy is to place a device distal to thestenosis during atherectomy to catch the pieces of the stenosis as theyare severed, and to remove those pieces along with the capturing devicewhen the atherectomy procedure is complete. Such capture devices haveincluded expandable filters which are placed distal of the stenosis tocapture stenosis fragments. Problems are also associated with thistechnique. For example, delivery of such devices in a low profile,pre-deployment configuration can be difficult. Further, some devicesinclude complex and cumbersome actuation mechanisms. Also, retrievingsuch capture devices, after they have captured emboli, can be difficultas well.

SUMMARY OF THE INVENTION

[0011] An emboli capturing system captures emboli in a body lumen. Afirst elongate member has a proximal end and a distal end. An expandableemboli capturing device is mounted proximate the distal end of the firstelongate member, and is movable between a radially expanded position anda radially contracted position. When in the expanded position, theemboli capturing device forms a basket with a proximally opening mouth.A second elongate member has a proximal and a distal end with a lumenextending therebetween. The lumen is sized to slidably receive a portionof the first elongate member. An expandable delivery device is mountedto the distal end of the second elongate member and is movable from aradially retracted position to a radially expanded position. Thedelivery device has a receiving end configured to receive the embolicapturing device, and retains at least the mouth of the emboli capturingdevice in a radially retracted position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 shows a distal protection device of the present inventionin a deployed position.

[0013]FIG. 2 shows the distal protection device shown in FIG. 1 in acollapsed position.

[0014]FIG. 3 shows an end view of a portion of the distal protectiondevice shown in FIGS. 1 and 2.

[0015]FIG. 4 shows a cross-sectional view of a portion of the distalprotection device shown in FIGS. 1-3 in the deployed position.

[0016]FIG. 5 shows a second embodiment of the distal protection deviceaccording to the present invention in a deployed position.

[0017]FIG. 6 shows an end view of the distal protection device shown inFIG. 5.

[0018]FIG. 7 shows a cross-sectional view of the distal protectiondevice shown in FIGS. 5 and 6 in the collapsed position.

[0019]FIG. 8 shows a third embodiment of a distal protection deviceaccording to the present invention in a deployed position.

[0020]FIG. 9 is a side sectional view of an alternate embodimentillustrating how the expandable members of the present invention areattached to a guidewire.

[0021]FIG. 10 is a sectional view taken along section lines 10 ⁻¹⁰ inFIG. 9.

[0022]FIGS. 11A and 11B show a fourth and fifth embodiment,respectively, of a distal protection device according to the presentinvention in a deployed position.

[0023]FIG. 12 illustrates the operation of a distal protection device inaccordance with the present invention.

[0024] FIGS. 13A-17B show additional embodiments of distal protectiondevices which expand and collapse based on movement of a mechanicalactuator.

[0025] FIGS. 18A-18D illustrate an additional embodiment of a distalprotection device which is deployed and collapsed using a rolling flapconfiguration.

[0026]FIG. 19 illustrates another embodiment in accordance with thepresent invention in which the protection device is deployed using fluidpressure and a movable collar.

[0027]FIGS. 20A and 20B illustrate another aspect of the presentinvention in which two longitudinally movable members used to deploy thedistal protection device are disconnectably locked to one another.

[0028] FIGS. 21A-21C illustrate another embodiment in accordance withthe present invention in which the protection device is formed with ashape memory alloy frame and an attached filter or mesh mounted to theframe.

[0029] FIGS. 22A-22C illustrate another embodiment in accordance withthe present invention in which the distal protection devices shown inFIGS. 21A-21C are delivered and deployed.

[0030] FIGS. 23A-23E illustrate another embodiment in accordance withthe present invention in which the distal protection devices shown inFIGS. 21A-21C are retrieved.

[0031] FIGS. 24A-24C illustrate another embodiment in accordance withthe present invention in which the distal protection devices shown inFIGS. 21A-21C are retrieved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032]FIG. 1 illustrates protection device 10 in a deployed positionwithin the lumen of a blood vessel 12. Protection device 10 preferablyincludes hollow guidewire 14 (or a hypotube having the same generaldimensions as a guidewire) having a coil tip 16, and a capturingassembly 18. Capturing assembly 18, in the embodiment shown in FIG. 1,includes an inflatable and expandable member 20 and mesh 22.

[0033] An interior of expandable member 20 is preferably coupled forfluid communication with an inner lumen of guidewire 14 at a distalregion of guidewire 14. When deployed, inflatable member. 20 inflatesand expands to the position shown in FIG. 1 such that capturing assembly18 has an outer periphery which approximates the inner periphery oflumen 12.

[0034] Mesh 22 is preferably formed of woven or braided fibers or wires,or a microporous membrane, or other suitable filtering or netting-typematerial. In one preferred embodiment, mesh 22 is a microporous membranehaving holes therein with a diameter of approximately 100 μm. Mesh 22can be disposed relative to inflatable member 20 in a number ofdifferent ways. For example, mesh 22 can be formed of a single generallycone-shaped piece which is secured to the outer or inner periphery ofinflatable member 20. Alternatively, mesh 22 can be formed as a spiralstrip which is secured about the outer or inner periphery of inflatablemember 20 filling the gaps between the loops of inflatable member 20.Alternatively, mesh 22 can be formed of a number of discrete pieceswhich are assembled onto inflatable member 20.

[0035] Hollow guidewire 14 preferably has a valve 24 coupled in aproximal portion thereof. During operation, a syringe is preferablyconnected to the proximal end of guidewire 14, which preferably includesa fluid hypotube. The syringe is used to pressurize the fluid such thatfluid is introduced through the lumen of hollow guidewire 14, throughvalve 24, and into inflatable member 20. Upon being inflated, inflatablemember 20 expands radially outwardly from the outer surface of guidewire14 and carries mesh 22 into the deployed position shown in FIG. 1. Inthis way, capturing assembly, or filter assembly, 18 is deployeddistally of stenosis 26 so that stenosis 26 can be severed andfragmented, and so the fragments from stenosis 26 are carried by bloodflow (indicated by arrow 28) into the basket or chamber formed by thedeployed filter assembly 18. Filter assembly 18 is then collapsed andremoved from vessel 12 with the fragments of stenosis 26 containedtherein.

[0036]FIG. 2 illustrates protection device 10 with filter assembly 18 inthe collapsed position. Similar items to those shown in FIG. 1 aresimilarly numbered. FIG. 2 illustrates that mesh 22 is easilycollapsible with inflatable member 20. In order to collapse filterassembly 18, fluid is preferably removed from inflatable member 20through the lumen of hollow guidewire 14 and through two-way valve 24.This can be done using the syringe to pull a vacuum, or using any othertype of suitable fluid removal system.

[0037] Inflatable member 20 is preferably formed of a material havingsome shape memory. Thus, when inflatable member 20 is collapsed, itcollapses to approximate the outer diameter of hollow guidewire 14. Inone preferred embodiment, inflatable member 20 is formed of a resilient,shape memory material such that it is inflated by introducing fluidunder pressure through the lumen in hollow guidewire 14 into inflatablemember 20. When pressure is released from the lumen in hollow guidewire14, inflatable member 20 is allowed to force fluid out from the interiorthereof through two-way valve 24 and to resume its initial collapsedposition. Again, this results in filter assembly 18 assuming itscollapsed position illustrated in FIG. 2.

[0038]FIG. 3 illustrates a view taken from the distal end of device 10with mesh 22 removed for clarity. FIG. 3 shows that, when inflatablemember 20 is deployed outwardly, mesh 22 (when deployed between theloops of inflatable member 20) forms a substantially lumen-fillingfilter which allows blood to flow therethrough, but which provides amechanism for receiving and retaining stenosis fragments carried intomesh 22 by blood flow through the vessel.

[0039]FIG. 3 also shows that inflatable member 20 preferably has aproximal end portion 29 which is connected to the outer periphery ofguidewire 14. Although end 29 need not be connected to guidewire 14, itis preferably connected using adhesive or any other suitable connectionmechanism. By fixedly connecting proximal end portion 29 to guidewire14, this increases the stability of the filter assembly 18 upondeployment.

[0040]FIG. 4 is a cross-sectional view of a portion of protection device10. FIG. 4 shows protection device 10 with filter assembly 18 in theexpanded or deployed position. FIG. 4 also better illustrates thatguidewire 14 is hollow and has a longitudinal lumen 30 extendingtherethrough. Longitudinal lumen 30 is connected in fluid communicationwith an interior of inflatable member 20 through aperture 32 which isprovided in the wall of guidewire 14. FIG. 4 also shows that, in onepreferred embodiment, a core wire 34 extends through lumen 30 from aproximal end thereof where it is preferably brazed to a portion of ahypotube which may be connected to the proximal portion of guidewire 14.The core wire 34 extends to the distal end of guidewire 14 where it isconnected to coil tip 16. In one preferred embodiment, coil tip 16 isbrazed or otherwise welded or suitably connected to the distal portionof core wire 34.

[0041]FIG. 4 further shows that, in the preferred embodiment, inflatablemember 20 inflates to a generally helical, conical shape to form abasket opening toward the proximal end of guidewire 14. FIG. 4 furtherillustrates, in the preferred embodiment, mesh 22 has a distal portion38 which is connected to the exterior surface of guidewire 14, at adistal region thereof, through adhesive 36 or any other suitableconnection mechanism.

[0042]FIG. 5 illustrates a second embodiment of a distal protectiondevice 40 in accordance with the present invention. Device 40 includeshollow guidewire 42, filter assembly 44 and coil tip 16. Filter assembly44 includes a plurality of inflatable struts 46 and mesh 47. Each strut46 has a distal end 48 and proximal end 50. Inflatable struts 46 alsohave an interior which is coupled in fluid communication, through distalend 48 thereof, with the lumen in hollow guidewire 42. Struts 46 arepreferably configured such that, upon being inflated, the proximal ends50 deploy radially outwardly away from the outer surface of hollowguidewire 42 to assume a dimension which approximates the innerdimension of lumen 58 in which they are inserted.

[0043] Mesh 47, as with mesh 22 shown in FIG. 1, is deployed either onthe outer or inner surface of inflatable struts 46, such that, when theinflatable struts 46 are deployed radially outwardly, mesh 47 forms agenerally conical basket opening toward the proximal end of hollowguidewire 42. As with the embodiment shown in FIG. 1, mesh 47 can beapplied to either the outer or the inner surface of struts 46. It can beapplied to struts 46 as one unitary conical piece which is adhered aboutdistal ends 48 of struts 46 using adhesive (or about the distal end ofguidewire 42 using adhesive) and secured to the surface of the struts 46also using adhesive. Alternatively, mesh 47 can be applied to struts 46in a plurality of pieces which are individually or simultaneouslysecured to, and extend between, struts 46.

[0044]FIG. 6 is an end view of distal protection device 40 shown in FIG.5 taken from the distal end of distal protection device 40. When struts46 are deployed outwardly, mesh 47 forms a substantially lumen-fillingfilter which allows blood to flow therethrough, but which provides amechanism for receiving and retaining stenosis fragments from stenosis56 carried into mesh 47 by blood flow through the vessel.

[0045]FIG. 7 is a cross-sectional view of a portion of distal protectiondevice 40 shown in FIGS. 5 and 6. FIG. 7 shows filter assembly 44 in thecollapsed position in which it approximates the outer diameter ofguidewire 42. FIG. 7 also shows that, in the preferred embodiment, thedistal ends 48 of struts 46 are in fluid communication with an innerlumen 52 in hollow guidewire 42 through apertures 54 in the wall ofguidewire 42.

[0046]FIG. 8 illustrates another embodiment of a distal protectiondevice 60 in accordance with the present invention. Distal protectiondevice 60 is similar to those shown in other figures, and similar itemsare similarly numbered. However, distal protection device 60 includeshollow guidewire 63 which has a lumen in fluid communication with aninterior of a pair of inflatable struts 62. Inflatable struts 62 have aninner surface 64 which is generally concave, or hemispherical, orotherwise appropriately shaped such that it extends about a portion ofthe outer surface of hollow guidewire 63. Mesh portions 66 extendbetween the inflatable struts 62 so that inflatable struts 62 and meshportions 66, when deployed outwardly as shown in FIG. 8, form a basketshape which opens toward the proximal end of hollow guidewire 63.

[0047]FIG. 9 illustrates another system for attaching inflatable strutsto a hollow guidewire for a distal protection device 70 in accordancewith the present invention. Distal protection device 70 is similar tothe distal protection devices shown in the previous figures in that aplurality of inflatable struts 72 are provided and preferably have amesh portion extending therebetween. For the sake of clarity, the meshportion is eliminated from FIG. 9. However, it will be understood that,when deployed, distal protection device 70 forms a generallybasket-shaped filter assembly which opens toward the proximal end ofhollow guidewire 74.

[0048] In the embodiment shown in FIG. 9, hollow guidewire 74 has adistal end 75 which is open. An endcap 76 is disposed about the distalend 75 of hollow guidewire 74 and defines an internal chamber orpassageway 78. Endcap 76 has a proximal end 80 which has openingstherein for receiving the ends of inflatable struts 72. Thus, in orderto inflate inflatable struts 72, the operator pressurizes fluid withinthe lumen of hollow guidewire 74 forcing fluid out through distal end 75of hollow guidewire 74, through passageway 78, and into inflatablestruts 72. In order to collapse distal protection device 70, theoperator draws a vacuum which pulls the fluid back out of inflatablestruts 72, through passageway 78 and, if necessary, into the lumen ofhollow guidewire 74.

[0049]FIG. 10 is an end view of endcap 76 taken along lines 10-10 inFIG. 9. FIG. 10 shows that proximal end 80 of endcap 76 preferablyincludes a first generally central aperture 82 for receiving the distalend of hollow guidewire 74. Aperture 82 is sized just larger than, orapproximating, the outer diameter of hollow guidewire 74 such that itfits snugly over the distal end 75 of hollow guidewire 74. Endcap 76 isthen fixedly connected to the distal end 75 of hollow guidewire 74through a friction fit, a suitable adhesive, welding, brazing, oranother suitable connection technique.

[0050]FIG. 10 also shows that proximal end 80 of endcap 76 includes aplurality of apertures 84 which are spaced from one another about end80. Apertures 84 are sized to receive open ends of inflatable struts 72.In the preferred embodiment, inflatable struts 72 are secured withinapertures 84 using a suitable adhesive, or another suitable connectiontechnique. Also, in the preferred embodiment, spring tip 16 is embeddedin, or otherwise suitably connected to, endcap 76.

[0051]FIGS. 11A and 111 show two other preferred embodiments of a distalprotection device in accordance with the present invention. FIG. 11Ashows distal protection device 90 which includes hollow guidewire 92having a lumen running therethrough, inflatable member 94 and meshportion 96. FIG. 11A shows that inflatable member 94, when inflated,forms a ring about the outer surface of hollow guidewire 92. The ringhas an inner periphery 98 which is spaced from the outer surface ofhollow guidewire 92 substantially about the entire radial periphery ofhollow guidewire 92. Mesh portion 96 extends between the outer surfaceof hollow guide 92 and the inner periphery 98 of inflatable member 94.Thus, a substantially disc-shaped filter assembly is provided upondeployment of distal protection device 90. As with the otherembodiments, deployment of distal protection device 90 is accomplishedby providing fluid through the inner lumen of hollow guidewire 92 intoan interior of inflatable member 94 which is in fluid communication withthe inner lumen of hollow guidewire 92.

[0052] In one preferred embodiment, end 100 of inflatable member 94 iscoupled to a coupling portion 102 of inflatable member 94 such thatstability is added to inflatable member 94, when it is inflated.

[0053]FIG. 11B illustrates another distal protection device 104 whichincludes a hollow guidewire 106 and an inflatable member 108. Device 104is similar to distal protection device 90 except that, rather thanhaving only a single inflatable ring upon deployment of distalprotection device 104, a plurality of generally equal-diameter rings areformed into a helix shape. In the preferred embodiment, distalprotection device 104 includes a mesh sleeve 110 which extends about theouter or inner surface of the helix formed by inflatable member 108. Inone embodiment, mesh sleeve 110 is connected to the outer surface ofhollow guidewire 106 in a region 112 proximate, but distal of,inflatable member 108. In another preferred embodiment, the proximal endof mesh sleeve 110 is connected to the outer perimeter of inflatablemember 108. Thus, distal protection device 104 forms a generallybasket-shaped filter assembly which opens toward a proximal end ofguidewire 106.

[0054] As with the other embodiments, both distal protection device 90shown in FIG. 11A and distal protection device 104 shown in FIG. 11B arepreferably collapsible. Therefore, when collapsed, the distal protectiondevices 90 and 104 preferably have an outer dimension which approximatesthe outer dimension of hollow guidewires 92 and 106, respectively.Further, as with the other embodiments, distal protection devices 90 and104 can either be biased in the deployed or collapsed positions, anddeployment and collapse can be obtained either by pulling a vacuum, orpressurizing the fluid within the lumen of the hollow guidewires 92 and106.

[0055]FIG. 12 illustrates the use of a distal protection device inaccordance with the present invention. For the sake of clarity, thepresent description proceeds with respect to distal protection device 10only. Device 10 is shown filtering stenosis fragments from the bloodflowing through the lumen of vessel 12. FIG. 12 also shows a dilatationdevice 120 which can be any suitable dilatation device for dilating,cutting, fragmenting, or abrading, portions of stenosis 26. In thepreferred embodiment, device 120 is used in an over-the-wire fashionover hollow guidewire 14. Thus, filter assembly 18 is first advanced(using guidewire 14) distal of stenosis 26. Then, filter assembly 18 isdeployed outwardly to the expanded position. Dilatation device 120 isthen advanced over guidewire 14 to stenosis 26 and is used to fragmentor abrade stenosis 26. The fragments are received within the basket offilter assembly 18. Filter assembly 18 is then collapsed, and filterassembly 18 and dilatation device 120 are removed from vessel 12.Alternatively, dilatation device 120 can be removed first and filterassembly 18 is then removed along with guidewire 14.

[0056] It should be noted that the stenosis removal device (oratherectomy catheter) 120 used to fragment stenosis 26 can be advancedover guidewire 14. Therefore, the device according to the presentinvention is dual functioning in that it captures emboli and serves as aguidewire. The present invention does not require adding an additionaldevice to the procedure. Instead, the present invention simply replacesa conventional guidewire with a multi-functional device.

[0057] FIGS. 13A-17B illustrate embodiments of various distal protectiondevices wherein deployment and contraction of the distal protectiondevice is accomplished through a mechanical push/pull arrangement.

[0058]FIGS. 13A and 13B illustrate a distal protection device 122. FIG.13A shows device 122 in an undeployed position and FIG. 13B shows device122 in a deployed position. Distal protection device 122 includes aslotted Nitinol tube 124 which has a lumen 126 extending therethrough.Tube 124 has a plurality of slots 128 at a distal region thereof. Thedistal portion of slots 128 are covered by mesh 130 which, in thepreferred embodiment, is a flexible microporous membrane. Device 122also preferably includes a mandrel 132 which extends through the innerlumen 126 of tube 124 and is attached to the distal end of tube 124. Inthe preferred embodiment, mandrel 132 is attached to the distal end oftube 124 by an appropriate adhesive, brazing, welding, or anothersuitable connection technique. Tube 124 also has, on its inner peripheryin a proximal region thereof, a plurality of locking protrusions 134.Lock protrusions 134 are preferably arranged about a proximal expandableregion 136 disposed on mandrel 132.

[0059] In order to deploy device 122 into the deployed position shown inFIG. 13B, the operator preferably first advances tube 124 distally ofthe lesion to be fragmented. In the preferred embodiment, tube 124 has asize on the order of a guidewire, such as a 0.014 inch outer diameter.Therefore, it easily advances beyond the stenosis to be fragmented. Theoperator then pushes on the proximal region of tube 124 and pulls on theproximal end of mandrel 132. This causes two things to happen. First,this causes the struts formed by slots 128 to expand radially outwardly,and carry with them, microporous membrane 130. Thus, microporousmembrane 130 forms a generally basket-shaped filter assembly which openstoward the proximal end of tube 124. In addition, proximal expandablemember 136 expands and engages protrusions 134. This locks device 122 inthe deployed and expanded position. In order to move the device 122 tothe collapsed position, the physician simply pushes on mandrel 132 andpulls on the proximal end of tube 124. This causes device 122 to returnto the undeployed position shown in FIG. 13A.

[0060] It should be noted that device 122 can optionally be providedwith a stainless steel proximal hypotube attachment. Also, the strutsdefined by slots 128 can be expanded and retracted using a fluidcoupling instead of a mandrel. In other words, the proximal end of tube124 can be coupled to a pressurizable fluid source. By making slots 128very thin, and pressurizing the fluid, the struts expand outwardly.Further, by pulling vacuum on the pressurizable fluid, the strutscollapse.

[0061]FIG. 14A illustrates distal protection device 140 which is similarto that shown in FIGS. 13A and 13B, except that the struts 142 areformed of a metal or polymer material and are completely covered by mesh144. Mesh 144 includes two mesh portions, 146 and 148. Mesh portion 146is proximal of mesh portion 148 on device 140 and is a relatively loosemesh which will allow stenosis fragments to pass therethrough. Bycontrast, mesh 148 is a fairly tight mesh, or a microporous membrane,(or simply loose mesh portion 146 with a microporous membrane or othersuitable filter material bonded or cast or otherwise disposed thereover)which does not allow the fragments to pass therethrough and thereforecaptures and retains the fragments therein. The mesh portions canprovide a memory set which, in the relaxed position, is either deployedor collapsed.

[0062]FIG. 14B illustrates a device 150 which is similar to device 140shown in FIG. 14A, except struts 142 are eliminated and the two meshportions 146′ and 148′ are-simply joined together at a region 152. Also,the two mesh portions 146′ and 148′ are not two different discrete meshportions but are formed of the same braided mesh material wherein thebraid simply has a different pitch. The wider pitch in region 146′provides a looser mesh, whereas the narrower pitch in region 148′provides a tighter mesh that traps the embolic material.

[0063]FIG. 14C illustrates a distal protection device 160 which issimilar to that shown in FIG. 14A. However, rather than simply providinga slotted tube, distal protection device 160 includes a plurality ofstruts 162 on a proximal region thereof and a plurality of struts 164 onthe distal region thereof. Struts 162 are spaced further apart thanstruts 164 about the periphery of protection device 160. Therefore,struts 162 define openings 166 which are larger than the openings 168defined by struts 164 and allow stenosis fragments to pass therethrough.Also, struts 164 have secured to the interior surface thereof a filteror mesh portion 170. When deployed, filter portion 170 forms asubstantially basket-shaped filter device opening toward the proximalregion of tube 172.

[0064]FIG. 15 illustrates the operation of another distal protectiondevice 176. Distal protection device 176 includes a tube 178 and apush/pull wire 180. Tube 178 has, at the distal end thereof, a filterassembly 182. Filter assembly 182 includes a plurality of preferablymetal struts 184 which have a microporous membrane, or other suitablemesh 186 disposed thereon. Tube 178 also preferably includes end cap 188and umbrella-like expansion structure 190 disposed at a distal regionthereof. Expansion structure 190 is connected to the distal region oftube 178 and to metal struts 184 such that, when push/pull wire 180 ispulled relative to tube 178, expansion member 190 exerts a radial,outwardly directed force on struts 184 causing them to expand radiallyoutwardly relative to the outer surface of tube 178. This causesmicroporous membrane or mesh 186 to be deployed in a manner openingtoward the proximal end of tube 178 to catch embolic material. Struts184 can also be formed of an appropriate polymer material.

[0065]FIGS. 16A and 16B illustrate a protection device in accordancewith another embodiment of the present invention. FIG. 16A illustratesdistal protection device 192. Device 192 includes guidewire 194,actuator wire 196, and filter assembly 198. Filter assembly 198 includesan expandable ring 200, such as an expandable polymer or metal or otherelastic material, which has attached thereto mesh 202. Mesh 202 is alsoattached to guidewire 194 distally of ring 200. Actuator wire 196 isattached to sleeve or sheath 204 which is positioned to fit about theouter periphery of expandable ring 200, when expandable ring 200 is inthe collapsed position

[0066] Thus, when sheath 204 is moved distally of expandable ring 200,expandable ring 200 has shape memory which causes it to expand into theposition shown in FIG. 16A. Alternatively, when sheath 204 is pulledproximally by pulling actuator wire 196 relative to guidewire 194,sheath 204 collapses ring 200 and holds ring 200 in the collapsedposition within sheath 204. Manipulating wires 194 and 196 relative toone another causes device 192 to move from the deployed position to thecollapsed position, and vice versa.

[0067]FIG. 16B is similar to device 192 except that, instead of havingan expandable ring 200 connected at one point to wire 194, distalprotection device 206 includes expandable member 208 which is formed ofan elastic coil section of wire 194. Thus, elastic coil section 208 hasa shape memory which causes it to expand into the generally helical,conical shape shown in FIG. 16B. However, when sheath 204 is pulledproximally relative to expandable member 208, this causes sheath 204 tocapture and retain expandable member 208 in a collapsed position. Whensheath 204 is again moved distally of expandable member 208, expandablemember 208 returns to its expanded position shown in FIG. 16B carryingwith it mesh 210 into a deployed position. In the preferred embodiment,sheath 204 is formed of a suitable polymer material and expandablemember 208 and expandable ring 200 are preferably formed of Nitinol.

[0068]FIGS. 17A and 17B illustrate the operation of another distalprotection device 212. Protection device 212 includes guidewire 214 andfilter assembly 216. In the preferred embodiment, filter assembly 216includes a wire braid portion 218 which extends from a distal region ofguidewire 214 proximally thereof. Braid portion 218 is formed of braidedfilaments or fibers which have a shape memory causing them to form adeployed, basket-shaped filter, such as that shown in FIG. 17A, in theunbiased position. Braided portion 218 terminates at its proximal end ina plurality of eyelets 220. One or more cinch wires 222 are preferablythreaded through eyelets 220. By pushing on guidewire 214 and pulling oncinch wires 222, the operator is able to cinch closed, and pullproximally, the proximal portion of mesh 218. This causes mesh 218 tocollapse tightly about the outer surface of wire 214.

[0069] Therefore, during operation, the operator holds mesh 218 in thecollapsed position and inserts protection device 212 distally of thedesired stenosis. The operator then allows cinch wire 222 to movedistally relative to guidewire 214. This allows mesh 218 to open to thedeployed position shown in FIG. 17A which has an outer diameter thatapproximates the inner diameter of the lumen within which it isdisposed. Filter assembly 216 is then disposed to capture embolicmaterial from blood flowing therethrough. Once the embolic material iscaptured, the operator again moves cinch wire 222 proximally relative toguidewire 214 to collapse filter assembly 216 and capture and retain theembolic material in filter assembly 216. The device 212 is then removed.

[0070]FIG. 17B shows distal protection device 212 except that in theembodiment shown in FIG. 17B, protection device 212 is not disposeddistally of the stenosis, but rather proximally. This results, forexample, in an application where the blood flow is proximal of thestenosis rather than distal. Further, in the embodiment shown in FIG.17B, guidewire 214 is preferably hollow and the cinch wire 222 extendsthrough the lumen therein. By pushing on guidewire 214, a force isexerted on mesh 218 in the distal direction. This causes cinch wire 222to tightly close the distal opening in filter assembly 216 and tocollapse mesh portion 218. By contrast, by allowing cinch wire 222 tomove distal relative to hollow guidewire 214, mesh portion 218 expandsand filter assembly 216 is deployed as shown in FIG. 17B.

[0071]FIGS. 18A and 18B illustrate a distal protection device 250 inaccordance with another aspect of the present invention. Device 250includes inner wire 252 and outer tube 254. In the preferred embodiment,inner wire 252 is a core wire and outer tube 254 has a lumen 256 thereinlarge enough to accommodate longitudinal movement of inner wire 252therein. Also, in the preferred embodiment, inner wire 252 has, coupledto its distal end 258, a spring tip 260.

[0072] Device 250 includes expandable mesh or braid portion 262.Expandable portion 262 has a proximal end 264 which is attached to thedistal end 266 of tube 254. Also, expandable member 262 has a distal end268 which is attached to the distal end 258 of inner wire 252.

[0073] Expandable member 262 is preferably a mesh or braided materialwhich is coated with polyurethane. In one preferred embodiment, a distalportion of expandable member 262 has a tighter mesh than a proximalportion thereof, or has a microporous membrane or other suitablefiltering mechanism disposed thereover. In another preferred embodiment,expandable member 262 is simply formed of a tighter mesh or braidedmaterial which, itself, forms the filter. FIG. 18A illustrates device250 in a collapsed, or insertion position wherein the outer diameter ofmesh portion 262 closely approximates the outer diameters of eitherinner wire 252 or outer tube 254.

[0074]FIG. 18B illustrates device 250 in the deployed position in whichexpandable member 262 is radially expanded relative to the collapsedposition shown in FIG. 18A. In order to deploy device 250, the outertube 254 is moved distally with respect to inner wire 252 such that thedistal ends 266 and 258 of wires 254 and 252 move longitudinally towardone another. Relative movement of ends 266 and 258 toward one anothercauses the mesh of expandable member 262 to buckle and fold radiallyoutwardly. Thus, the outer diameter of expandable member 262 in thedeployed position shown in FIG. 18B closely approximates the innerdiameter of a vessel within which it is deployed.

[0075]FIG. 18C illustrates device 250 in a partially collapsed position.In FIG. 18C, the distal end 266 of outer tube 254 and the distal end 258of inner wire 252 are moved even closer together than they are as shownin FIG. 18B. This causes expandable mesh portion 262 to fold over itselfand form a rolling, proximally directed flap 270. As longitudinalmovement of inner wire 252 proximally with respect to outer tube 254continues, mesh portion 262 continues to fold over itself such that therolling flap portion 270 has an outer radial diameter which continues todecrease. In other words, expandable mesh portion 262 continues to foldover itself and to collapse over the outer periphery of outer tube 254.

[0076]FIG. 18D illustrates device 250 in a fully collapsed position inwhich it retains emboli captured therein. In FIG. 18D, the distal end266 of outer tube 254 has been advanced as far distally as it canrelative to the distal end 258 of inner wire 252. This causes expandablemesh portion 262 to fold all the way over on itself such that it liesagainst, and closely approximates the outer diameter of, outer tube 254.Device 250 thus captures any emboli filtered from the vessel withinwhich it was deployed, and can be removed while retaining that embolicmaterial.

[0077]FIG. 19 illustrates device 280 which depicts a further aspect inaccordance with the present invention. Device 280 includes outer tube282, core wire 284, transition tube 286, movable plunger 288, expandablemember 290, fixed collar 292 and bias member 294.

[0078] In the preferred embodiment, tube 282 comprises a proximalhypotube which is coupled to a plunger that selectively provides fluidunder pressure through an inflation lumen 296. Inner wire 284 ispreferably a tapered core wire which terminates at its distal end in aspring coil tip 298 and which is coupled at its proximal end 300 totransition tube 286. Transition tube 286 is preferably an outer polymersleeve either over hypotube 282, or simply disposed by itself andcoupled to a hypotube 282. Transition tube 286 is capable ofwithstanding the inflation pressure provided by the fluid deliveredthrough the inflation lumen 296.

[0079] Movable collar 288 is preferably slidably engageable with theinterior surface of transition tube 286 and with the exterior surface ofcore wire 284, and is longitudinally movable relative thereto. Slidablecollar 288 has, attached at its distal end, bias spring 294 which ispreferably coiled about core wire 284 and extends to fixed collar 292.Fixed collar 292 is is preferably fixedly attached to the exteriorsurface of a distal portion of core wire 284.

[0080] Expandable member 290 is preferably formed, at a proximal portionthereof, of either discrete struts, or another suitable frame (such as aloose mesh) which allows blood and embolic material to flowtherethrough. The proximal end 302 of expandable member 290 is coupledto a distal region of movable collar 288. The distal portion ofexpandable member 290 is preferably formed of a filtering material whichis suitable for allowing blood flow therethrough, but which will captureembolic material being carried by the blood.

[0081] In one preferred embodiment, spring 294 is biased to forcecollars 288 and 292 away from one another. Thus, as spring 294 urgescollars 288 and 292 away from one another, collar 288 retracts withintransition tube 286 pulling expandable member 290 into a collapsedposition about core wire 284. However, in order to deploy collapsiblemember 290 as shown in FIG. 19, the operator preferably actuates aplunger (not shown) which delivers pressurized fluid through lumen 296.The pressurized fluid enters transition tube 286 and travels about theouter periphery of inner core wire 284, thus forcing movable collar 288to move distally along core wire 284. This overcomes the spring forceexerted by spring 294 thus causing collars 288 and 292 to move towardone another, relatively. This motion causes expandable member 290 tobuckle and expand outwardly to the deployed position shown in FIG. 19.

[0082] Expandable member 290 is collapsed by releasing the pressureapplied through lumen 296 (i.e., by causing the plunger to moveproximally). This allows spring 294 to again urge collars 288 and 292away from one another to collapse expandable member 290. In analternative embodiment, the frame supporting expandable member 290 isimparted with a memory (such as a heat set, or a thermally responsivematerial which assumes a memory upon reaching a transition temperature)such that the resting state of the frame supporting expandable member290 is in a collapsed position. This eliminates the need for spring 294.The expandable member 290, in that preferred embodiment, is expandedusing the hydraulic pressure provided by the pressurized fluidintroduced through lumen 296, and it is collapsed by simply allowing thememory in expandable member 290 to force fluid from transition tube 286back through lumen 296.

[0083]FIGS. 20A and 20B illustrate another aspect in accordance with thepresent invention. A device 310 includes a mesh portion 312 supported bya frame 314. Expansion of frame 314 to the radially expanded positionshown in FIG. 20A is driven by an expandable member, such as a balloon316 which is coupled to frame 314. Balloon 316 is coupled to a distalend of a distal hypotube 318, which is formed of a suitable material,such as nitinol. It should be noted that the distal tip of hypotube 318includes a spring tip 320.

[0084] Distal hypotube 318 is shown coupled to a proximal hypotube 322which has a tapered portion 324 therein. In the preferred embodiment,proximal hypotube 322 is formed of a suitable material, such asstainless steel. A plunger 326 is longitudinally movable within thelumen of both proximal hypotube 322 and distal hypotube 318.

[0085] Frame 314, and consequently mesh portion 312, are deployed by theoperator moving plunger 326 distally within the lumens of hypotubes 318and 322. This causes pressurized fluid to enter balloon 316, therebyinflating balloon 316 and driving deployment of frame 314 and mesh 312.In order to collapse frame 314 and mesh 312, the operator preferablymoves plunger 326 proximally within the lumens of tubes 318 and 322 towithdraw fluid from within balloon 316. Alternatively, mesh 312 or frame314 can have a memory set which is either in the inflated or collapsedposition such that the operator need only affirmatively move frame 314and mesh 312 to either the deployed or collapsed position, whichever isopposite of the memory set.

[0086] In either case, it is desirable that the operator be able to lockplunger 326 in a single longitudinal position relative to hypotubes 318and 322. Thus, device 310 includes a locking region 328.

[0087]FIG. 20B illustrates locking region 328 in greater detail. FIG.20B illustrates that, in locking region 328, plunger 326 has a pluralityof grooves 330 formed in the outer radial surface thereof. Also, inaccordance with the present invention, FIG. 20B illustrates that one ofhypotubes 318 or 322 has an inwardly projecting portion 332. In onepreferred embodiment, inwardly projecting portion 332 includes aninwardly extending, deflectable, annular rim which extends inwardly fromeither hypotube 318 or 322. In another preferred embodiment, theinwardly projecting portion 332 includes a plurality of discrete fingerswhich extend inwardly from one of hypotubes 318 or 322 and which areangularly displaced about the interior periphery of the correspondinghypotube 318 or 322.

[0088] In operation, as the operator advances plunger 326 distallywithin the lumens of hypotubes 318 and 322, inwardly projecting portion332 rides along the exterior periphery of plunger 326 until itencounters one of grooves 330. Then, inwardly projecting portion 332snaps into the groove 330 to lock plunger 326 longitudinally relative totubes 318 and 322.

[0089] It should be noted that, in the preferred embodiment, bothinwardly projecting portions 332 and grooves 330 are formed such that,when gentle pressure is exerted by the operator on plunger 326 relativeto hypotubes 318 and 322, projection portions 332 follow the contour ofgrooves 330 up and out of grooves 330 so that plunger 326 can again befreely moved within the lumens of hypotubes 318 and 322. Thus, therelative interaction between projecting portions 332 and grooves 330provides a ratcheting type of operation wherein plunger 326 can bereleasably locked into one of a plurality longitudinal positionsrelative hypotubes 318 and 322, since a plurality of grooves 330 areprovided. Plunger 326 can be moved back and forth longitudinally withinthe lumens of hypotubes 318 and 322 in a ratcheting manner and can belocked into one of a plurality of relative longitudinal positionsbecause there are a plurality of grooves 330 in the exterior of plunger326. It should also be noted, however, that in another preferredembodiment, a plurality of sets of inwardly projecting portions 332 areprovided along the inner longitudinal surface of hypotubes 318 and/or322. In that case, only a single groove 330 needs to be formed in theexterior surface of plunger 326; and the same type of ratcheting lockingoperation is obtained.

[0090] In the preferred embodiment, at least the exterior of hypotubes318 and 322, and preferably the exterior of plunger 326, are tapered.This allows device 310 to maintain increased flexibility. It should alsobe noted that, in the preferred embodiment, hypotubes 318 and 322 arepreferably sized as conventional guidewires.

[0091]FIG. 21A illustrates a protection device in accordance withanother embodiment of the present invention. FIG. 21A illustrates distalprotection device 340. Device 340 is similar to devices 192 and 206shown in FIGS. 16A and 16B. However, in the preferred embodiment, device340 includes hoop-shaped frame 342, filter portion 344, and wire 346.Hoop-shaped frame 342 is preferably a self-expanding frame formed of awire which includes a shape memory alloy. In a more preferred embodimenthoop-shaped frame 342 is formed of a nitinol wire having a diameter in arange of approximately 0.002-0.004 inches.

[0092] Filter portion 344 is preferably formed of a polyurethanematerial having holes therein such that blood flow can pass throughfilter 344, but emboli (of a desired size) cannot pass through filter344 but are retained therein. In one preferred embodiment, filtermaterial 344 is attached to hoop-shaped frame 342 with a suitable,commercially available adhesive. In another preferred embodiment, filter344 has a proximal portion thereof folded over hoop-shaped frame 342,and the filter material is attached itself either with adhesive, bystitching, or by another suitable connection mechanism, in order tosecure it about hoop-shaped frame 342. This connection is preferablyformed by a suitable adhesive or other suitable connection mechanism.

[0093] Also, the distal end of filter 344 is preferably attached aboutthe outer periphery of wire 346, proximate coil tip 348 on wire 346.

[0094] In one preferred configuration, filter 344 is approximately 15 mmin longitudinal length, and has a diameter at its mouth (defined byhoop-shaped frame 342) of a conventional size (such as 4.0 mm, 4.5 mm, 5mm, 5.5 mm, or 6 mm). Of course, any other suitable size can be used aswell.

[0095] Also, in the preferred configuration, filter 344 is formed of apolyurethane material with the holes laser drilled therein. The holesare preferably approximately 100 μm in diameter. Of course, filter 344can also be a microporous membrane, a wire or polymer braid or mesh, orany other suitable configuration.

[0096] Wire 346 is preferably a conventional stainless-steel guidewirehaving conventional guidewire dimensions. For instance, in oneembodiment, wire 346 is a solid core wire having an outer diameter ofapproximately 0.014 inches and an overall length of up to 300 cm. Also,in the preferred embodiment, wire 346 has a distal end 350, in a regionproximate filter 344, which tapers from an outer diameter at itsproximal end which is the same as the outer diameter of the remainder ofwire 346, to an outer diameter of approximately 0.055 inches at itsdistal end. At distal region 350, guidewire 346 is preferably formed ofstainless steel 304.

[0097] Of course, other suitable guidewire dimensions and configurationscan also be used. For example guidewires having an outer diameter ofapproximately 0.018 inches may also be used. For other coronaryapplications, different dimensions may also be used, such as outerdiameters of approximately 0.010 inches to 0.014 inches. Further, itwill be appreciated that the particular size of wire 346 will vary withapplication. Applications involving neural vasculature will require theuse of a smaller guidewire, while other applications will require theuse of a larger guidewire. Also, wire 346 can be replaced by a hollowguidewire, or hypotube of similar, or other suitable dimensions.

[0098] In addition, in order to make wire 342, hoop 346, or filter 344radiopaque, other materials can be used. For example, radiopaque loadedpowder can be used to form a polyurethane sheath which is fitted overwire 346 or hoop 342, or which is implemented in filter 344. Also, hoop342 and wire 346 can be gold plated in order to increase radiopacity.Also, marker bands can be used on wire 346 or filter 344 to increase theradiopacity of the device.

[0099] In operation, hoop 342 (and thus filter 344) is preferablycollapsed to a radially contracted position which more closelyapproximates the outer diameter of wire 346. Methods of performing thiscontraction are described later in the specification. Once retracted toa more low profile position, wire 346 is manipulated to position hoop342 and filter 344 distal of a restriction to be treated. Then, therestraining force which is used to restrain hoop 342 in thepredeployment, low profile position is removed, and the superelasticproperties of nitinol hoop 342 (or the shape memory properties ofanother shape memory alloy) are utilized in allowing hoop 342 to assumeits shape memory position. This causes hoop 342 to define asubstantially lumen filling mouth to filter 344 which is positioneddistal of the restriction to be treated.

[0100] A suitable dilatation device is then advanced over wire 346 andis used to treat the vascular restriction. Emboli which are carried byblood flow distal of the restriction are captured by filter 344. Afterthe dilatation procedure, filter 344, along with the emboli retainedtherein, are retrieved from the vasculature. Various retrievalprocedures and devices are described later in the specification.

[0101] By allowing hoop-shaped frame 342 to be unattached to wire 346,and only connected to wire 346 through filter 344 (or other superstructure used to support filter 344), wire 346 is allowed tosubstantially float within hoop 342. This configuration provides someadvantages. For instance, hoop 342 can better follow the vasculaturewithout kinking or prolapsing (i.e., without collapsing upon itself).Thus, certain positioning or repositioning of filter 344 can beaccomplished with less difficulty.

[0102]FIG. 21B illustrates a protection device 352 in accordance withanother embodiment of the present invention. Protection device 352 issimilar to protection device 340, and similar items are similarlynumbered. However, rather than having simply a hoop-shaped frame 342 tosupport filter 344, and drive filter 344 into its expanded and deployedposition, device 352 includes frame 354 which includes a hoop-shapedportion 356, and a pair of tails 358 and 360.

[0103] Tails 358 and 360 extend proximally from hoop-shaped portion 356to an attachment region 362. In the preferred embodiment, tails 358 and360 are attached to wire 346 at attachment region 362 by soldering,welding, brazing, adhesive, or any other suitable attachment mechanism.In the embodiment shown in FIG. 21B, attachment sleeve 364, formed of aweldable material, is attached at its inner periphery to tails 358 and360. Sleeve 364 is then attached, using welding or brazing, to wire 346.

[0104] By providing tails 358 and 360, frame 354 is directly connectedto wire 346. However, tails 358 and 360 are provided so that the pointof attachment of frame 354 to wire 346 is located several millimetersproximal of hoop-shaped portion 356. This provides some additionalstructural integrity to frame 354, but still allows frame 354 tosubstantially float about wire 346 in the region of hoop-shaped frameportion 356.

[0105]FIG. 21C illustrates a protection device 366 in accordance withanother embodiment of the present invention. Protection device 366 issimilar to protection devices 340 and 352 shown in FIGS. 21A and 21B,and similar items are similarly numbered. However, device 366 includeshoop-shaped frame 368. Frame 368 is similar to frame 342 shown in FIG.21A. However, unlike frame 342, hoop 368 does not allow wire 346 tofloat freely therein. Instead, hoop 368 is directly attached to wire 346at attachment point 370. This causes hoop-shaped frame 368 and filter344 to reside eccentrically about wire 346.

[0106] FIGS. 22A-22C illustrate one preferred embodiment for deliveringone of devices 340, 352 and 366. For the sake of clarity, only device352 is illustrated in FIGS. 22A-22C.

[0107]FIG. 22A illustrates delivery device 372. In the preferredembodiment, delivery device 372 includes proximal hub 374, shaft 376,and distal retaining section 378. Also, in one preferred embodiment,device 372 also includes marker band 380. In the preferred embodiment,delivery device 372 is similar to a conventional balloon catheter inthat proximal hub 374 is a conventional hub, and shaft 376 is aconventional balloon catheter shaft. Further, distal retaining section378 is preferably a conventional angioplasty balloon having an inflateddiameter of approximately 1.5-2.0 millimeters, but having its distal endcutoff such that the distal end 382 of balloon 378 is open.

[0108] Prior to insertion of device 372 into the vasculature,hoop-shaped frame 354 is retracted into its low profile deploymentposition and is withdrawn through end 382 into balloon 378. Then, thedistal end of balloon 378 is exposed to heat to heat shrink or heat setthe distal end of balloon 378 around the radially retracted device 352.Device 372, including device 352, is then inserted in the vasculatureeither through a preplaced guide catheter, along with a guide catheter,or simply without a guide catheter utilizing coil tip 348.

[0109] In any case, once device 372 is properly placed such that balloon378 is located distal of the restriction to be treated, distalprotection device 352 is then removed from within heat collapsed balloon378. In one preferred embodiment, the physician simply accomplisheslongitudinal movement of wire 346 relative to catheter 376. Forinstance, the physician may simply hold wire 346 longitudinally in placeand withdraw catheter 376 proximally relative to wire 346 by pulling onhub 374. This causes balloon 378 to move proximally relative to device352, and thereby to expose device 352 to the vasculature.

[0110]FIG. 22B illustrates another preferred embodiment for removingdevice 352 from within balloon 378. In the embodiment shown in FIG. 22B,syringe 384, which contains fluid, is inserted into coupling 386 in hub374. The physician then introduces pressurized fluid into the lumen ofcatheter 376. The pressurized fluid advances down the lumen of catheter376 to the distal end where it encounters collapsed balloon 378. Thepressure exerted on balloon 378 by the pressurized fluid causes balloon378 to open radially. Then, the physician withdraws catheter 376relative to device 352 thereby exposing device 352 to the vasculature.

[0111] In any case, once device 352 is no longer restrained by balloon378, device 352 assumes its shape memory position in the vasculature, asillustrated in FIG. 22C. Thus, device 352 substantially forms alumen-filling basket or filter which allows blood to pass distallytherethrough, but which retains or captures embolic material carried bythe blood flow. The physician then simply removes device 372 from thevasculature, leaving device 352 in place during subsequent procedures.In one preferred embodiment, shaft 376 includes a predefined slit orscore from a region just proximal of marker band 380 to, or through, hub374. Thus, as the physician removes device 372, it can be peeled awayfrom device 352. Also, or alternatively, device 372 can be provided withan aperture in shaft 376 near its distal end. The proximal end of wire346 will thus lie outside of shaft 376. Wire 346 can enter shaft 376through the aperture and extend through the distal end of shaft 376.This also facilitates easier withdrawal of device 372 over wire 346.

[0112] FIGS. 23A-23E illustrate one preferred embodiment for retrievingone of the devices 340, 352 and 366 described in FIGS. 21A-21C. For thesake of clarity, only device 352 is illustrated in FIGS. 23A-23E. FIG.23A illustrates retrieval device 388. Retrieval device 388 is preferablyformed of proximal shaft 390, mesh portion 392, and end cap 394. Items390, 392 and 394 preferably each have lumens therein to define apassageway for receiving wire 346. Also, wire 346 may optionally beprovided with an positive stop 396 (which can be embodied as aradiopaque marker band) Optional stop 396 may also simply be an annularring attached to wire 346 proximate to filter 344, or may be any othersuitable stop.

[0113] Proximal shaft 390 is preferably simply a polymer or nitinol tubesized and configured to track over wire 346. End cap 394 is alsopreferably formed to track over wire 346, but also contains radiopaquematerial to serve as a distal marker band for retrieval device 388. Mesh392 is preferably a braid or mesh formed of wire or polymer materialhaving sufficient flexibility that it can be deflected as describedbelow.

[0114] Mesh 392 preferably has a proximal end coupled to proximal shaft390, by adhesive, welding, or other suitable attachment mechanisms. Mesh392 also preferably includes a distal end connected to end cap 394, alsoby a suitable connection mechanism.

[0115] In order to retrieve filter 344, which likely contains embolicmaterial, device 388 is inserted in the low profile position shown inFIG. 23A, over wire 346, to a position proximate filter 344. Then,device 388 is advanced toward filter 344, until end cap 394 abutspositive stop 396, or the hoop-shaped frame 354. Continued advancementof proximal shaft 390 relative to wire 346 causes compression of mesh392. This results in a radial expansion of an intermediate portion ofmesh 392 (between the proximal and distal ends of mesh 392). The radialexpansion of mesh portion 392 is illustrated in FIG. 23B.

[0116] By continuing to advance proximal shaft 390 relative to wire 346,the intermediate portion of mesh 392 is configured to bend over onitself such that it is axially displaced toward filter 344, in thedirection generally indicated by arrows 398 in FIG. 23C. In thepreferred embodiment, mesh 392 is sized and configured such that, withcontinued advancement OL proximal shaft 390 relative to wire 346, thisaction continues as shown in FIGS. 23D and 23E until the intermediateportion of mesh 392 encompasses at least the mouth of filter 344. Also,in the preferred embodiment, the intermediate portion of mesh 392, whendriven as described above, engages and contracts the mouth of filter 344to a lower profile position, such as that shown in FIG. 23E. In yetanother preferred embodiment, mesh 392 is sized and configured tosubstantially engulf the entire filter 344.

[0117] Once at least the mouth of filter 344 is encompassed by mesh 392,device 388, along with device 352, are simply withdrawn from thevasculature. In one preferred embodiment in which a guide catheter isused, devices 388 and 352 are simply withdrawn either into the guidecatheter and the guide catheter is removed with those devices,simultaneously, or devices 388 and 352 are removed from the guidecatheter prior to removal of the guide catheter. In another preferredembodiment, in which no guide catheter is used, devices 388 and 352 aresimply removed from the vasculature simultaneously.

[0118] It will also be appreciated, of course, that rather thanproviding device 388 with a single proximal tube 390 and end cap 394, asecond actuation tube or wire can also be provided which is attached toend cap 394, and which extends back through the lumen in proximal tube390 and is longitudinally movable relative to proximal shaft 390. Inthat way, the actuation wire or elongate member can be used to pull cap394 closer to the distal portion of proximal shaft 390 in order toaccomplish the action illustrated in FIGS. 23A-23E. This feature is alsoillustrated in FIGS. 18A-18D which illustrate the mesh portion foldedproximally rather than distally.

[0119] FIGS. 24A-24C illustrate another preferred embodiment inaccordance with the present invention, for retrieving any of the distalprotection devices 340, 352 or 366 shown in FIGS. 21A-21C. For the sakeof clarity, only device 352 is illustrated in FIGS. 24A-24C.

[0120]FIG. 24A illustrates retrieval device 400. Retrieval device 400preferably includes retrieval sheath 402, proximal locking device 404,dilator sheath 405, and nose cone 406. In the preferred embodiment,retrieval sheath 402 is preferably formed of polyether block amide(PEBAX) material having an outer diameter of approximately six French(i.e., approximately 2 mm) and having a shore D hardness ofapproximately 40. Also, retrieval sheath 402 preferably has a wallthickness of approximately 0.004 inches. Dilator sheath 405, and nosecone 406, are preferably formed of low density polyethylene, or highdensity polyethylene. Sheath 405 preferably has an outer diameter whichis approximately equal to the inner diameter of sheath 402. In addition,the inner diameter of sheath 405 and nose cone 406 is preferably justlarge enough to fit over, and track over, wire 346. Nose cone 406preferably has a proximal portion which is either attached to, or formedintegrally with, sheath 405. The outer diameter of the proximal portionof nose cone 406 is also approximately the same as the outer diameter ofsheath 405. However, nose cone 406 also preferably has a distal portionwhich tapers, or reduces along preferably a smooth curve, to an outerdiameter which terminates at the inner diameter of nose cone 406.

[0121] Proximal locking device 404 is preferably any suitable, andcommercially available, locking device which can be configured to lockdilator sheath 405 to guidewire 346.

[0122] In order to retrieve device 352 from the vasculature, device 400is preferably advanced over guidewire 346 to a position shown in FIG.24B, in which the distal portion of nose cone 406 is closely proximate,or adjacent to, either optional stop 396 or the mouth of filter 344.Then, proximal locking device 404 is actuated to lock dilator sheath 405to wire 346 so that wire 346 and dilator sheath 405 (as well as nosecone 406) can be moved as a unitary piece.

[0123] Next, wire 346 (and hence dilator sheath 405 and nose cone 406)are withdrawn longitudinally relative to retrieval sheath 402. Thiscauses the mouth of filter 344 to enter within the distal opening inretrieval sheath 402. This results in device 352 being positionedrelative to sheath 402 as shown in FIG. 24C. Of course, wire 346,dilator sheath 405 and nose cone 406 can be withdrawn further intosheath 402 such that the entire filter 344, and wire tip 348, aredisposed within the lumen of sheath 402.

[0124] In any case, once at least the mouth of filter 344 is withinsheath 402, device 352 is configured to be removed from the vasculature.This can be accomplished by either removing dilator sheath 405, nosecone 406 and device 352 as a unitary piece, leaving sheath 402 in placefor later removal, or by removing sheath 402 with the remainder of thesystem, either through a guide catheter or simply through thevasculature, simultaneously. Also, where a guide catheter is used,device 352 and device 400 can be removed through the guide catheterleaving the guide catheter in place, or the guide catheter can beremoved simultaneously with the other devices 352 and 400.

[0125] It should be noted that all of the devices according to thepresent invention can optionally be coated with an antithromboticmaterial, such as heparin (commercially available under the tradenameDuraflow from Baxter), to inhibit clotting.

[0126] Thus, in accordance with one preferred embodiment of the presentinvention, the superelastic properties of nitinol are used to form aframe at least in the area of the mouth of the distal protection filter.Thus, the distal protection device can be deployed, retrieved, andre-deployed any number of times without incurring plastic deformation.In addition, in other preferred embodiments in accordance with thepresent invention, various deployment and retrieval techniques andsystems are provided which address various problems associated with suchsystems.

[0127] Although the present invention has been described with referenceto preferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

What is claimed is:
 1. An emboli capturing system for capturing emboliin a body lumen, comprising: a first elongate member having a proximalend and a distal end; an expandable emboli capturing device mountedproximate the distal end of the first elongate member, the embolicapturing device being movable between a radially expanded position anda radially retracted position, the expandable emboli capturing deviceforming a basket with a proximally opening mouth when in the radiallyexpanded position; a second elongate member having a proximal end and adistal end and a lumen extending between the proximal and distal ends,the lumen being sized to slidably receive a portion of the firstelongate member therein; and an expandable delivery device mounted tothe distal end of the second elongate member and being movable from aradially retracted position to a radially expanded position, thedelivery device having a receiving end configured to receive the embolicapturing device, the delivery device retaining at least the mouth ofthe emboli capturing device in the radially retracted position when thedelivery device is in the radially retracted position, the embolicapturing device being longitudinally movable out from within thedelivery device when the delivery device is in the radially expandedposition.
 2. The emboli capturing system of claim 1 and furthercomprising: a retrieval device, configured to be longitudinally movablerelative to the emboli capturing device in the body lumen and having areceiving end configured to receive at least the mouth of the embolicapturing device when the emboli capturing device is in the radiallyexpanded position.
 3. The emboli capturing system of claim 2 wherein theretrieval device comprises the expandable delivery device in theradially expanded position.
 4. The emboli capturing system of claim 2wherein the receiving end of the retrieval device is contractible from aradially expanded position to a radially contracted position to at leastpartially collapse the emboli capturing device therein.
 5. The embolicapturing system of claim 4 wherein the retrieval device comprises: athird elongate member having proximal and distal ends and a lumenextending therebetween, the lumen being sized to slidably receive atleast a portion of the first elongate member therein, the lumen at thedistal end of the third elongate member forming the receiving end andbeing sized to receive a most radially expanded portion of the embolicapturing device; and a fourth elongate member movable within the lumenof the third elongate member, the fourth elongate member having anintermediate region sized to substantially fill the receiving end and adistal tip having an outer diameter less than an outer diameter of theintermediate region.
 6. The emboli capturing system of claim 5 whereinthe distal tip of the fourth elongate member is configured with anaperture therein sized to track over the first elongate member.
 7. Theemboli capturing system of claim 6 wherein the fourth elongate member isformed in a substantially conical shape between the distal tip thereofand the intermediate region thereof.
 8. The emboli capturing system ofclaim 2 wherein the retrieval device includes: a third elongate memberhaving proximal and distal ends and a lumen extending therebetween, thelumen being sized to slidably receive at least a portion of the firstelongate member; and a mesh sleeve having a first end coupled to thethird elongate member, a second end distal of the first end and anintermediate portion between the first and second ends, the mesh sleevebeing configured such that relative longitudinal movement of one of thefirst and second ends thereof relative to another of the first andsecond ends thereof drives movement of the mesh portion from a radiallyretracted position, to a radially expanded position in which theintermediate portion expands radially outward relative to the first andsecond ends, and to a collapsed position in which the mesh sleeve bendssuch that the intermediate portion is displaced in a direction towardone of the first and second ends of the mesh sleeve.
 9. The embolicapturing system of claim 8 wherein the retrieval device is configuredsuch that sufficient longitudinal movement of the emboli capturingdevice toward the mesh sleeve causes the emboli capturing device todrive the second end of the mesh sleeve toward the first end of the meshsleeve.
 10. The emboli capturing system of claim 9 wherein the meshsleeve is sized to encompass at least the mouth of the emboli capturingdevice as the mesh sleeve moves from the radially expanded position tothe collapsed position.
 11. The emboli capturing system of claim 2wherein the retrieval device includes: a third elongate member havingproximal and distal ends and a lumen extending therebetween, the lumenbeing sized to slidably receive at least a portion of the first elongatemember; a fourth elongate member longitudinally movable relative to thethird elongate member; and a mesh sleeve having a first end coupled tothe third elongate member and a second end coupled to the fourthelongate member and an intermediate portion between the first and secondends, the mesh sleeve being configured such that relative longitudinalmovement of one of the third and fourth elongate members relative toanother of the third and fourth elongate members drives movement of themesh portion from a radially retracted position, to a radially expandedposition in which the intermediate portion expands radially outwardrelative to the first and second ends, and to a collapsed position inwhich the mesh sleeve bends such that the intermediate portion isdisplaced in a direction toward one of the first and second ends of themesh sleeve.
 12. The emboli capturing system of claim 1 wherein thereceiving end of the delivery device is defined by a portion of adilatation balloon.
 13. The emboli capturing system of claim 1 whereinthe receiving end of the delivery device is thermally shrunk over atleast the mouth of the emboli capturing device to retain the embolicapturing device in the radially contracted position during delivery.14. The emboli capturing system of claim 1 wherein the receiving end ofthe delivery device is movable from the radially retracted position tothe radially expanded position by delivery of pressurized fluid throughthe lumen in the second elongate member.
 15. The emboli capturing systemof claim 1 wherein the emboli capturing device is a self-expandingdevice biased in the radially expanded position.
 16. The embolicapturing system of claim 15 wherein the emboli capturing deviceincludes: a frame formed of a shape memory alloy; and a filter portionsupported by the frame, the filter portion being configured to permitblood flow therethrough and to capture emboli carried by blood flowtherethrough.
 17. The emboli capturing system of claim 16 wherein thefilter portion has a first end connected to the first elongate memberand a second end connected to the frame and wherein the frame comprises:a loop disposed about the first elongate member to define the mouth ofthe emboli capturing device.
 18. The emboli capturing system of claim 17wherein the loop is directly connected to the first elongate member. 19.The emboli capturing system of claim 17 wherein the shape memory alloycomprises an alloy having superelastic properties.
 20. The embolicapturing system of claim 19 wherein the shape memory alloy includesnitinol.
 21. The emboli capturing system of claim 20 wherein the embolicapturing device is substantially conical in shape.
 22. The embolicapturing system of claim 21 wherein the filter portion comprises apolyurethane member having a plurality of holes therein.
 23. The embolicapturing system of claim 1 wherein the first elongate member comprisesa guidewire.
 24. A method of capturing emboli carried by flow of fluidthrough a body lumen, the method comprising: providing a first elongatemember having a proximal end and a distal end; providing an expandableemboli capturing device mounted proximate the distal end of the firstelongate member, the emboli capturing device being movable between aradially expanded position and a radially retracted position, theexpandable emboli capturing device defining a proximally opening mouthwhen in the radially expanded position; providing a second elongatemember having a proximal end and a distal end and a lumen extendingbetween the proximal and distal ends, the lumen being sized to slidablyreceive a portion of the first elongate member therein; providing anexpandable delivery device mounted to the distal end of the secondelongate member and being movable from a radially retracted position toa radially expanded position, the delivery device having a receiving endconfigured to receive the emboli capturing device, the delivery deviceretaining at least the mouth of the emboli capturing device in theradially retracted position when the delivery device is in the radiallyretracted position; inserting the expandable delivery device into thelumen with the mouth of the emboli capturing device retained in theradially retracted position within the delivery device; expanding theexpandable delivery device into the radially expanded position; andlongitudinally moving the delivery device relative to the embolicapturing device to remove the emboli capturing device from within thedelivery device.
 25. The method of claim 24 and further comprising:providing a retrieval device, configured to be longitudinally movablerelative to the emboli capturing device in the body lumen and having areceiving end configured to receive at least the mouth of the embolicapturing device when the emboli capturing device is in the radiallyexpanded position; and longitudinally moving the delivery devicerelative to the emboli capturing device such that at least the mouth ofthe emboli capturing device is in the receiving end of the retrievaldevice.
 26. The method of claim 25 wherein the receiving end of theretrieval device is contractible from a radially expanded position to aradially contracted position, and further comprising: contracting thereceiving end of the retrieval device to at least partially collapse theemboli capturing device therein.
 27. The method of claim 26 whereinproviding a retrieval device comprises: providing a third elongatemember having proximal and distal ends and a lumen extendingtherebetween, the lumen being sized to slidably receive at least aportion of the first elongate member therein, the lumen at the distalend of the third elongate member forming the receiving end and beingsized to receive a most radially expanded portion of the embolicapturing device; providing a fourth elongate member movable within thelumen of the third elongate member, the fourth elongate member having anintermediate region sized to substantially fill the receiving end and adistal tip having an outer diameter less than an outer diameter of theintermediate region; advancing the third and fourth elongate membersover the first elongate member, with the intermediate region of thefourth elongate member positioned within the third elongate member tofill the receiving end thereof, to a point proximate the embolicapturing device; withdrawing the distal tip of the fourth elongatemember within the lumen of the third elongate member; and positioning atleast the mouth of the emboli capturing device within the receiving endof the retrieval device.
 28. The method of claim 27 and furthercomprising: withdrawing the first, third, and fourth elongate membersfrom the body lumen.
 29. The method of claim 25 wherein providing theretrieval device includes: providing a third elongate member havingproximal and distal ends and a lumen extending therebetween, the lumenbeing sized to slidably receive at least a portion of the first elongatemember; providing a mesh sleeve having a first end coupled to the thirdelongate member, a second end distal of the first end and anintermediate portion between the first and second ends, the mesh sleevebeing configured such that relative longitudinal movement of one of thefirst and second ends thereof relative to another of the first andsecond ends thereof drives movement of the mesh portion from a radiallyretracted position, to a radially expanded position in which theintermediate portion expands radially outward relative to the first andsecond ends, and to a collapsed position in which the mesh sleeve bendssuch that the intermediate portion is displaced in a direction towardone of the first and second ends of the mesh sleeve; advancing the thirdelongate member into the body lumen over the first elongate member to apoint proximate the mouth of the emboli capturing device; andaccomplishing relative longitudinal movement of the emboli capturingdevice and the mesh sleeve toward one another, driving the second end ofthe mesh sleeve toward the first end of the mesh sleeve such that themesh sleeve encompasses at least the mouth of the emboli capturingdevice as the mesh sleeve moves from the radially expanded position tothe collapsed position.
 30. The method of claim 24 wherein expandingcomprises: delivering pressurized fluid through the lumen in the secondelongate member.